In recent years, with the expansion of mail-orders, a transaction volume of objects (also referred to as goods or work) is increasing in the field of physical distribution. Meanwhile, labor shortages, with a backdrop of an aging society with fewer children, are a concern within the country, and needs for saving manpower, automation of distribution centers, and the like are rapidly increasing. In the latest distribution centers, material handling devices are used for automated storage, acceptance or delivery, conveyance, and sorting. As a holding mechanism of the material handling devices, a mechanism that is arranged in a tip end of a multi-joined manipulator and that clamps an object with two holding parts is often employed. Work to pick and pack objects needs to include the ability to hold a wide variety of objects. For example, in a case of holding a large object, the holding parts need to be largely driven and thus the holding mechanism is increased in size. In a case of accurately holding a soft object, a sensor that senses a state of the object and a surrounding environment needs to be provided and thus the holding mechanism is increased in size and is complicated.
In this way, with the increase in the size of the holding mechanism, an object placed in a narrow space cannot be accurately held and many operations are still human-intensive. Further, accurately sensing the state of the object and the surrounding environment is difficult and the held object is sometimes damaged.
Development of a holding mechanism that achieves both downsizing of the holding mechanism and sensing of the object state has been desired.